Field of the Invention
The present invention relates to a transparent display device, and more particularly to a transparent display device which may improve visibility owing to improved diffraction and a manufacturing method thereof.
Discussion of the Related Art
Development of an information-oriented society is gradually increasing demands for display devices in various forms. Accordingly, various flat panel display devices, such as Liquid Crystal Display (LCD), Plasma Display Panel (PDP), Electro Luminescent Display (ELD), Vacuum Fluorescent Display (VFD) devices, and the like, have recently been studied. Some of these mentioned devices have already been utilized as display devices for various facilities.
Lately, in particular, transparent display devices, which are capable of displaying images while allowing an object at the rear thereof to be viewed, have actively been studied. By applying these transparent display devices to the windshield of a car, a glass of home appliances, and the like, provision of information is possible.
FIGS. 1A and 1B are respectively a perspective view and a photograph showing a transparent display device used in an application apparatus according to a related art, and FIG. 2 is photograph of the transparent display device having a diffraction grating according to the related art.
In the case in which the transparent display device 10, which includes an upper polarizer plate 10b, a liquid crystal panel 10a, and a lower polarizer plate 10c is applied to an application apparatus 20, such as a cooler door, as exemplarily shown in FIG. 1A, the transparent display device 10 is adapted to display images while allowing an object at the rear thereof to be viewed under the assistance of light inside the application apparatus 20.
The transparent display device 10 includes a plurality of pixel areas containing a regular array of lines and electrodes, the lines and the electrodes serving as a diffraction grating. More specifically, when the pixel areas of the transparent display device 10 are driven in an in-plane switching mode in which pixel electrodes and common electrodes alternate with each other to generate a transverse field, the pixel electrodes and the common electrodes arranged in parallel causes diffraction grating depending on wavelengths of light as light inside the application apparatus 20 passes through the display device 10. Severe diffraction grating, as exemplarily shown in FIG. 2, generates rainbow-colored spots due to mixing of several wavelengths of light, which causes boundaries of objects inside the application apparatus to appear blurry and also causes ghosting.